U.S. patent application number 09/754198 was filed with the patent office on 2001-09-06 for mounting structure for mounting power elements to heat dissipation member.
This patent application is currently assigned to CALSONIC KANSEI CORPORATION. Invention is credited to Oba, Takeshi, Ohira, Shigenori, Sano, Narihito, Sunaga, Hideki, Yamada, Kazunori.
Application Number | 20010019473 09/754198 |
Document ID | / |
Family ID | 18578104 |
Filed Date | 2001-09-06 |
United States Patent
Application |
20010019473 |
Kind Code |
A1 |
Sunaga, Hideki ; et
al. |
September 6, 2001 |
Mounting structure for mounting power elements to heat dissipation
member
Abstract
A power element mounting structure for use in a brushless motor
comprises a circuit board; a spring plate of metal, the spring
plate being resiliently mounted, through a first mounting
structure, on the circuit board keeping a given space therebetween;
a plurality of power elements disposed on the spring plate to form
a semi-assembled unit; a heat dissipation member of metal having a
plurality of heat dissipation fins on an outer surface thereof, the
heat dissipation member being mounted, through a second mounting
structure, on the semi-assembled unit in such a manner that an
inner surface thereof faces toward the power elements; and a
plurality of spring pieces defined by the spring plate, the spring
pieces being arranged to press the power elements against the inner
surface of the heat dissipation member.
Inventors: |
Sunaga, Hideki; (Gunma,
JP) ; Ohira, Shigenori; (Ibaraki, JP) ; Sano,
Narihito; (Tochigi, JP) ; Yamada, Kazunori;
(Tochigi, JP) ; Oba, Takeshi; (Tochigi,
JP) |
Correspondence
Address: |
Richard L. Schwaab
FOLEY & LARDNER
Washington Harbour
3000 K Street, N.W., Suite 500
Washington
DC
20007-8696
US
|
Assignee: |
CALSONIC KANSEI CORPORATION
|
Family ID: |
18578104 |
Appl. No.: |
09/754198 |
Filed: |
January 5, 2001 |
Current U.S.
Class: |
361/697 ;
257/E23.086 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H01L 23/4093 20130101; H02K 11/33 20160101; H05K 7/209 20130101;
H01L 2924/00 20130101; H01L 2924/0002 20130101 |
Class at
Publication: |
361/697 |
International
Class: |
H05K 007/20 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 2, 2000 |
JP |
2000-057287 |
Claims
What is claimed is:
1. A structure comprising: a circuit board; a spring plate of
metal, said spring plate being resiliently mounted, through a first
mounting structure, on said circuit board keeping a given space
therebetween; a plurality of power elements disposed on said spring
plate to form a semi-assembled unit; a heat dissipation member of
metal having a plurality of heat dissipation fins on an outer
surface thereof, said heat dissipation member being mounted,
through a second mounting structure, on said semi-assembled unit in
such a manner that an inner surface thereof faces toward said power
elements; and a plurality of spring pieces defined by said spring
plate, said spring pieces being arranged to press said power
elements against the inner surface of said heat dissipation
member.
2. A structure as claimed in claim 1, in which said spring pieces
are those pressed out of a main portion of said spring plate and
raised toward the inner surface of said heat dissipation
member.
3. A structure as claimed in claim 2, in which said main portion of
said spring plate is formed with a plurality of spaced projections
which extend along a longitudinal axis of said main portion, each
power element being put between adjacent two of said
projections.
4. A structure as claimed in claim 3, in which each of said power
elements has an exposed lead frame which is pressed against the
inner surface of said heat dissipation member by means of the
corresponding spring piece.
5. A structure as claimed in claim 4, in which said main portion of
said spring plate is formed with front and rear hedge portions
between which the aligned power elements are sandwiched.
6. A structure as claimed in claim 5, in which each of said power
elements has terminals whose leading ends are exposed to outside
defined below said circuit board through openings formed in the
main portion of said spring plate and openings formed in said
circuit board, said leading ends being soldered to given portions
of said circuit board.
7. A structure as claimed in claim 1, in which said first mounting
structure comprises: two supporting lugs integrally provided at
axially opposed ends of said spring plate; and two engaging notches
formed at laterally opposed ends of said circuit board, said
engaging notches respectively receiving said supporting lugs when
the spring plate is mounted on said circuit board.
8. A structure as claimed in claim 7, in which said second mounting
structure comprises: two mounting lugs integrally provided at
axially opposed ends of said heat dissipation member, the mounting
lugs being formed with respective recesses which face each other;
and bent portions provided at leading ends of said supporting lugs
of said spring plate, said bent portions being received in said
respective recesses of said mounting lugs of said heat dissipation
member when said heat dissipation member is mounted on said
semi-assembled unit.
9. A structure as claimed in claim 8, in which each of said
mounting lugs of said heat dissipation member is formed at its
inner surface with projections which are arranged to support said
semi-assembled unit.
10. A structure as claimed in claim 1, in which said first mounting
structure comprises: a plurality of leg portions integrally
provided at periphery of said spring plate; and a plurality of
engaging openings formed in said circuit board, said engaging
openings catching said leg portions when said spring plate is
mounted on said circuit board.
11. A structure as claimed in claim 10, in which one of said leg
portions and one of the engaging openings are so constructed as to
establish a latched connection therebetween when moved away from
each other by a given distance.
12. A structure as claimed in claim 11, in which said second
mounting structure comprises: two mounting lugs integrally provided
at axially opposed ends of said heat dissipation member, the
mounting lugs being formed with respective supporting grooves which
face each other; and lateral edges of said circuit board, said
lateral edges being received in said supporting grooves of said
mounting lugs of said heat dissipation member when said heat
dissipation member is mounted on said semi-assembled unit.
13. A structure as claimed in claim 12, in which each of said
lateral edges of said circuit board is formed with an exposed
earthed area which is soldered to the corresponding supporting
groove of said heat dissipation member.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to mounting structures for
mounting power elements to a heat dissipation member, and more
particularly to the mounting structures of a type that is suitable
for a brushless motor.
[0003] 2. Description of the Prior Art
[0004] As is known, a power element is a control element that
controls voltage and/or current and generates a certain heat under
operation. For effectively removing such heat, various mounting
structures have been proposed and put into practical use. One of
them is disclosed in Laid-open Japanese Patent Application
2000-32729, whose essential portion is shown in FIG. 20 of the
accompanying drawings. In this mounting structure, heat generated
from the power element is transferred to a heat dissipation member
through a heat sink. In the drawing, denoted by numeral 105 is a
power element. The power element 105 contacts to a leg portion 107
of a heat sink 101. The heat sink 101 is formed with a plurality of
heat dissipation fins 103 which serve as the heat dissipation
member. Terminals 109 of the power element 105 are soldered to a
circuit on a circuit board 111. The leg portion 107 of the heat
sink 101 is connected to the circuit board 111 by means of a bolt
113. As shown, the power element 105 is pressed against a surface
115 of the leg portion 107 by means of a spring member 117. Thus,
under operation, heat generated from the power element 105 is
transferred to the heat dissipation fins 103 through the leg
portion 107.
[0005] However, in this conventional power element mounting
structure, provision of the leg portion 107 causes increase in
length of a so-called heat travelling path and thus makes the heat
dissipation effect poor. Furthermore, in this mounting structure,
the leg portion 107 needs a certain strength and thus a larger size
because it has to hold the power element 105 and has to serve as a
good heat transferring means. Of course, in this case, the power
element mounting structure becomes bulky, heavy and costly.
SUMMARY OF THE INVENTION
[0006] It is therefore an object of the present invention to
provide a structure for mounting power elements to a heat
dissipation member, which is free of the above-mentioned
drawbacks.
[0007] According to the present invention, there is provided a
structure which comprises a circuit board; a spring plate of metal,
the spring plate being resiliently mounted, through a first
mounting structure, on the circuit board keeping a given space
therebetween; a plurality of power elements disposed on the spring
plate to form a semi-assembled unit; a heat dissipation member of
metal having a plurality of heat dissipation fins on an outer
surface thereof, the heat dissipation member being mounted, through
a second mounting structure, on the semi-assembled unit in such a
manner that an inner surface thereof faces toward the power
elements; and a plurality of spring pieces defined by the spring
plate, the spring pieces being arranged to press the power elements
against the inner surface of the heat dissipation member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Other objects and advantages of the present invention will
become apparent from the following description when taken in
conjunction with the accompanying drawings, in which:
[0009] FIG. 1 is a front view of a power element mounting structure
which is a first embodiment of the present invention;
[0010] FIG. 2 is a plan view of the power element mounting
structure of the first embodiment;
[0011] FIG. 3 is a side view taken from the direction of the arrow
"III" of FIG. 1;
[0012] FIG. 4 is an enlarged view of the part indicated by
reference "IV" of FIG. 1;
[0013] FIG. 5 is a front view of a heat dissipation member that
constitutes a part of the power element mounting structure of the
first embodiment;
[0014] FIG. 6 is a plan view of the heat dissipation member;
[0015] FIG. 7 is a front view of a spring member that constitutes a
part of the power element mounting structure of the first
embodiment;
[0016] FIG. 8 is a plan view of the spring member;
[0017] FIG. 9 is a plan view of a circuit board that constitutes a
part of the power element mounting structure of the first
embodiment;
[0018] FIG. 10 is a front view of a semi-assembled unit that
includes the circuit board having the spring member mounted
thereon;
[0019] FIG. 11 is a front view of the semi-assembled unit with some
power elements being mounted thereon;
[0020] FIG. 12 is a view similar to FIG. 11, but showing a
condition wherein all power elements are mounted on the
semi-assembled unit;
[0021] FIG. 13 is a perspective view of the power element;
[0022] FIG. 14 is a sectional view of a brushless motor which has
the power element mounting structure of the first embodiment
practically installed therein;
[0023] FIG. 15 is a view similar to FIG. 5, but showing a heat
dissipation member employed in a second embodiment of the present
invention;
[0024] FIG. 16 is a view similar to FIG. 9, but showing a circuit
board employed in the second embodiment of the present
invention;
[0025] FIG. 17 is a view similar to FIG. 1, but showing a power
element mounting structure of the second embodiment of the
invention;
[0026] FIG. 18 is a plan view of the power element mounting
structure of the second embodiment;
[0027] FIGS. 19A and 19B are illustrations showing the process of
properly mating a leg portion of the spring member with a holding
opening formed in the circuit board, in case of the second
embodiment; and
[0028] FIG. 20 is an enlarged sectional view of a part of a
conventional power element mounting structure.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0029] In the following, embodiments of the present invention will
be described in detail with reference to the accompanying drawings.
For ease of understanding, various directional terms, such as,
upward, downward, rightward, leftward, right, left, upper, lower
and the like will be used in the following description. However,
these terms are to be understood with respect to only the drawing
or drawings on which corresponding members or portions are
illustrated.
[0030] Referring to FIGS. 1 to 14, there is shown a power element
mounting structure 100A which is a first embodiment of the present
invention.
[0031] First, a brushless motor 1 which has the power element
mounting structure 100A installed therein will be described with
reference to FIG. 14.
[0032] In FIG. 14, there is shown in a sectional manner the
brushless motor 1. As will become apparent as the description
proceeds, the power element mounting structure 100A is constructed
to mount a plurality of power elements 29 to a heat dissipation
member 5.
[0033] The brushless motor 1 is mounted on a control case 7 and
comprises a motor shaft 13. The motor shaft 13 rotatably held by
upper and lower bearings 11a and 11b that are installed in a fixed
housing 9 that is raised from the control case 7. A cup-shaped yoke
17 concentrically fixed to the motor shaft 13 to rotate therewith.
A plurality of magnets 15 are disposed on a cylindrical inner
surface of the yoke 17 at equally spaced intervals. A stator 25 is
fixedly installed within the yoke 17, which comprises a plurality
of cores 23 arranged to surround the fixed housing 9. Each core 23
has a wound coil 21 fixed thereto and has an insulating member 19
facing the inner surface of the yoke 17.
[0034] Within the control case 7, there is arranged a drive circuit
section 27 which feeds the stator 25 with a controlled electric
power to rotate a unit including the motor shaft 13 and the yoke
17. The drive circuit section 27 comprises condensers, power
connectors and the plurality of power elements 29. Each of these
power elements 29 controls switching of current flowing
therethrough.
[0035] In the following, the power element mounting structure 100A
of the first embodiment will be described in detail with reference
to the drawings.
[0036] As is seen from FIG. 13, for effective heat dissipation,
each power element 29 is of an exposed type that has a lead frame
31 which is exposed from a plastic housing 30. MOS type field
effect transistors are installed in the housing 30. Of course, if
desired, the power element 29 may be of a non-exposed type in which
the lead frame 31 is covered with a plastic or the like. Three
terminals 33 extend outward from the casing 30.
[0037] Referring back to FIG. 14, the terminals 33 of each power
element 29 are soldered to given portions of a circuit board 35
which is fixedly installed in the control case 7. As is seen from
FIGS. 1, 4 and 13, the exposed lead frame 31 of each power element
29 is raised up from a back side of the casing 30, and as is best
understood from FIG. 4, the lead frame 31 abuts against a back
surface 5a of the heat dissipation member 5. For this abutting, a
spring plate 37 (see FIGS. 7 and 8) is used for pressing the lead
frame 31 against the back surface 5a. The spring plate 37 is made
of a metal.
[0038] As is seen from FIG. 5, the back surface 5a of the heat
dissipation member 5 is lined with an electrically insulating heat
dissipation sheet 39. Thus, the abutting of the lead frame 31
against the back surface 5a is made with interposal of the sheet 39
therebetween. The heat dissipation member 5 is made of a metal
material having a high thermal conductivity. The heat dissipation
member 5 is formed at both ends thereof with mounting lugs 41 which
extend in the same direction. The heat dissipation member 5 is
formed on a major portion thereof with a plurality of heat
dissipation fins 43 which are spaced from one another.
[0039] As is seen from FIG. 5, each of the mounting lugs 41 of the
heat dissipation member 5 is formed at an inner surface thereof
with a first projection 45, a second projection 47 and a spring
supporting portion 49.
[0040] The first projection 45 has a slanted surface 45a that faces
downward. As is understood from FIG. 1, upon assembly, aligned
power elements 29 are arranged between the first projections 45 of
the mounting lugs 41. Furthermore, as is seen from FIG. 4, upon
assembly, there is defined a clearance "d" between the lead frame
31 of the rightmost (or leftward) power element 29 and the inner
surface of the right (or left) mounting lug 41 of the heat
dissipation member 5.
[0041] As is seen from FIG. 4, upon assembly, the second projection
47 of each mounting lug 41 is in abutment with an end of the
circuit board 35.
[0042] As is seen from FIGS. 4 and 9, each end of the circuit board
35 is formed with a shallow recess 51 along which the corresponding
mounting lug 41 slides down when the heat dissipation member 5 is
pushed down for its assemblage.
[0043] As is seen from FIG. 9, each shallow recess 51 is formed
with an engaging notch 52 whose width is substantially the same as
that of an after-mentioned supporting lug 63 of the spring plate
37. The circuit board 35 is formed with six sets of small openings
67 which are aligned. Each set includes three aligned openings 67.
As will become apparent hereinafter, each set of openings 67 has
the three terminals 33 of the power element 29 passed
therethrough.
[0044] As is seen from FIGS. 4 and 5, the spring supporting portion
49 of each mounting lug 41 comprises a rectangular recess which
includes upper and lower horizontal surfaces 49a and 49c and a
vertical surface 49b.
[0045] As is seen from FIG. 4, upon assembly, a leading end of the
supporting lug 63 formed on each end of the spring plate 37 is put
into the corresponding recess (49a, 49b, 49c) in a snap action
manner, and at the same time, a major portion of the supporting lug
63 is received in the engaging notch 52 of the circuit board
35.
[0046] As is seen from FIGS. 7 and 8, the spring plate 37 is
rectangular in shape and has a width substantially equal to that of
the above-mentioned heat dissipation member 5. The spring plate 37
is formed at both sides of a major portion 55 thereof with front
and rear hedge portions 61. As is understood from FIG. 7, the
spring plate 37 is formed at longitudinal ends thereof with
respective supporting lugs 63 which extend in the same direction.
Each supporting lug 63 comprises a horizontal portion 63a and a
slanted portion 63b. As is seen from FIG. 4, upon assembly of the
spring plate 37, the slanted portion 63b thereof is deeply engaged
with the recess (49a, 49b, 49c) of the mounting lug 41 of the heat
dissipation member 5.
[0047] Referring back to FIGS. 7 and 8, particularly FIG. 8, the
spring plate 37 is formed with six identical openings 65 which are
aligned along the axis of the plate 37. Each opening 65 is formed
with a rectangular spring piece 59. Furthermore, the spring plate
37 is formed with five identical smaller projections 57, each being
arranged between adjacent two of the openings 65. As is seen from
the drawings, the spring pieces 59 and the smaller projections 57
are provided by pressing out of the main portion 55 of the spring
plate 37 and raising them upward. As is understood from FIG. 11,
upon assembly, each power element 29 is put between adjacent two of
the projections 57, and each spring piece 59 presses and biases the
power element 29 upward, and at the same time, the front and rear
hedge portions 61 of the spring plate 37 press front and rear
surfaces of each power element 29. Due to provision of the front
and rear hedge portions 61, stiffness of the spring plate 37 is
increased. As is seen from FIGS. 8 and 11, the three terminals 33
of each power element 33 pass through the corresponding opening 65
of the spring plate 37.
[0048] In the following, the process of assembling the mounting
structure 100A will be described with reference to the
drawings.
[0049] As is shown in FIG. 10, the spring plate 37 is mounted onto
the circuit board 35 from the above to provide a first
semi-assembled unit "1-UT". In this unit "1-UT", the supporting
lugs 63 of the spring plate 37 are respectively received in the
engaging notches 52 (see FIG. 9) formed at laterally opposed ends
of the circuit board 35. Due to the resiliency possessed by the
supporting lugs 63, the first semi-assembled unit "1-UT" shows a
certain self-holding characteristic.
[0050] Then, as is seen from FIGS. 11 and 12, six power elements 29
are mounted on the major portion 55 of the spring plate 37 one by
one in the above-mentioned manner. In this condition, each power
element 29 is sandwiched between adjacent two of the smaller
projections 57 and between the front and rear hedge portions 61 of
the spring plate 37, having the three terminals 33 passed through
the corresponding opening 65 of the spring plate 37 and through the
three small openings 67 of the circuit board 35. With this, the
power elements 29 are properly positioned on the spring plate 37
while being kept apart from one another by the aligned smaller
projections 57 of the spring plate 37. That is, as is seen from
FIG. 12, a second semi-assembled unit "2-UT" is provided.
[0051] Then, as is seen from FIGS. 1 and 4, the heat dissipation
member 5 is mounted on the second semi-assembled unit "2-UT" in a
manner to cover the six power elements 26. As may be seen from FIG.
4, during this mounting, the slanted surface 45a of the first
projection 45 on each mounting lug 41 of the heat dissipation
member 5 may slidably contact the outer surface of the rightmost
(or leftmost) power element 29. However, this contacting allow the
power element 29 to take the right position. Upon proper mounting
on the second semi-assembled unit "2-UT", the heat dissipation
member 5 is supported on the circuit board 35 by the second
projections 47 of the mounting lugs 41. At the same time, the
supporting lugs 36 of the spring plate 37 are engaged with the
spring supporting portions 49 of the mounting lugs 41 of the heat
dissipation member 5. Upon this, due to function of the spring
pieces 59 of the spring plate 37, the lead frames 31 of the power
elements 29 are biased to abut against the back surface 5a of the
heat dissipation member 5. With this, a third semi-assembled unit
"3-UT" is provided.
[0052] Then, the third semi-assembled unit "3-UT" is led to a
soldering line to put the back surface of the circuit board 35 into
a soldering pot. With this, the terminals 33 of the six power
elements 29 are soldered to given portions of the circuit board 35
at the same time and thus the power element mounting structure 100A
is finally produced.
[0053] In the mounting structure 100A, there is provided a shorter
heat transferring passage for each power element 29, that extends
from the back surface 5a of the heat dissipation member 5 to the
heat dissipation fins 43 of the same. That is, the heat generated
by each of the power element 29 can be instantly and effectively
transferred to the heat dissipation fins 43. As is understood from
the above, the mounting structure 100A is easily assembled, which
allows reduction in production cost. The aligned six power elements
29 are substantially wholly enclosed by the heat dissipation member
5 of metal, the spring plate 37 of metal and the front and rear
hedge portions 61 of the spring plate 37, and thus, noise radiation
from the power elements 29 is effectively suppressed. If a minus
terminal of an electric connector (not shown) is connected to a
body structure of the brushless motor 1 through an earth portion of
the circuit board 35, such noise shielding is much effectively
achieved.
[0054] Referring to FIGS. 15 to 19B, particularly FIGS. 17 and 18,
there is shown a power element mounting structure 100B which is a
second embodiment of the present invention.
[0055] Since the second embodiment 100B is similar in construction
to the above-mentioned first embodiment 100A, only parts and/or
portions different from those of the first embodiment 100A will be
described in the following.
[0056] As is seen from FIG. 15, the mounting lugs 41' of the heat
dissipation member 5' employed in the second embodiment 100B are
each provided with a supporting groove 69. As is seen from FIG. 16,
the circuit board 35' employed in the second embodiment 100B has at
both sides exposed earthed areas 71 which, upon assembly, are to be
slid into the supporting grooves 69 of the heat dissipation member
5'. Furthermore, the circuit board 35' is formed at a rear end
portion thereof with three spaced engaging openings 77 and at a
generally center portion thereof with a holding opening 78. The
holding opening 78 has a narrower section 79 which extends forward.
The engaging openings 77 and the holding opening 78 are those to
which leg portions of the spring plate 37' are engaged.
[0057] That is, as is seen from FIGS. 19A and 19B, in addition to
the above-mentioned parts 57, 59 and 61 possessed by the spring
plate 37 of the first embodiment 100A, the spring plate 37'
employed in the second embodiment 100B has further at a front
center portion a leg portion 75 and at a rear end portion the three
spaced leg portions (not shown). The spring plate 37' has no
structure corresponding to the supporting lugs 63 possessed by the
spring plate 37 of the first embodiment 100A.
[0058] The leg portion 75 is so sized as to pass through the
holding opening 78 and has a narrower part 81 that extends
downward. The narrower part 81 has a bent end 81a. As is seen from
these drawings, the narrower part 81 is so sized as to pass through
the narrower section 79 of the holding opening 78 of the circuit
board 35'. Although not shown in the drawings, the other three leg
portions formed at the rear end portion of the spring plate 37'
have each a catch portion that, upon assembly, catches the
corresponding engaging opening 77 of the circuit board 35'. It is
to be noted that these three leg portions and the above-mentioned
leg portion 75 are constructed to expand outward when no stress is
applied thereto. Thus, when these four leg portions 75 are mated
with the corresponding engaging and holding openings 77 and 78 and
then, as is seen from FIGS. 19A and 19B, the spring plate 37' is
lifted by a certain distance from the circuit board 35', the
narrower part 81 of the leg portion 75 of the spring plate 37'
becomes in engagement with the narrower section 79 of the holding
opening 78 of the circuit board 35' resulting in that the spring
plate 37' is latched to the circuit board 35' keeping a certain
space therebetween.
[0059] In the following, the process of assembling the mounting
structure 100B of the second embodiment will be described.
[0060] First, the spring plate 37' is temporarily mounted on the
circuit board 35' in the above-mentioned manner, and then the six
power elements 29 are mounted on the major portion of the spring
plate 37' in substantially the same manner as in the case of the
first embodiment 100A. Then, the heat dissipation member 5' is
mounted on the circuit board 35' in a manner to cover the six power
elements 26. For this mounting, the lateral edges, more
specifically, the exposed earthed areas 71 of the lateral edges of
the circuit board 35' are slid into the supporting grooves 69 of
the heat dissipation member 5'. Then, as is seen from FIGS. 19A and
19B, the spring plate 37' is lifted causing the narrower part 81 of
the leg portion 75 of the spring plate 37' to latched engaged with
the narrower section 79 of the holding opening 78 of the circuit
board 35'. With this, each power element 29 is pressed against the
back surface 5'a of the heat dissipation member 5'. Then, the
semi-assembled unit is led to a soldering line to put the back
surface of the circuit board 35' into a soldering pot. With this,
the terminals 33 of the six power elements 29 are soldered to given
portions of the circuit board 35' and at the same time the exposed
earthed areas 71 of the circuit board 35' are soldered to the
supporting grooves 69 of the heat dissipation member 5', and thus
the power element mounting structure 100B is finally produced.
[0061] Like in the above-mentioned first embodiment 100A, also in
this second embodiment 100B, there is provided a shorter heat
transferring passage for each power element 29, that extends from
the back surface 5'a of the heat dissipation member 5' to the heat
dissipation fins 43 of the same. In the second embodiment 100B,
much robust structure is achieved due to the soldering between the
exposed earthed areas 71 of the circuit board 35' and the
supporting grooves 6 of the heat dissipation member 5'.
[0062] The entire contents of Japanese Patent Application
P2000-057287 (filed Mar. 2, 2000) are incorporated herein by
reference.
[0063] Although the invention has been described above with
reference to the embodiments of the invention, the invention is not
limited to the embodiments described above. Various modifications
and variations of the embodiments described above will occur to
those skilled in the art, in light of the above teachings.
* * * * *